<h2 class="OptionGroupTitle">Sistema</h2>
<ul class="OptionGroup">
  <li><%= link_to 'Principal', url_for(:only_path => false), :class => "Option" %></li>
  <li><%= link_to 'Segurança', url_for(:only_path => false), :class => "Option" %></li>
  <% unless session[:usuario] %>
      <li><%= link_to 'Acessar', url_for(:only_path => false, :controller => '/autenticacao', :action => 'logon'), :class => :Option %></li>
  <% else %>
      <li><%= link_to 'Sair', url_for(:only_path => false, :controller => '/autenticacao', :action => 'logoff'), :class => :Option %></li>
  <% end %>
</ul>